Ever wonder how difficult it would be to unlock those sliding chain locks common to hotels, dorm rooms, and apartments? If you've got a rubber band, apparently it's not that difficult at all.

Blogger and lock-picker extraordinaire Barry Wels demonstrates how to unlock a sliding chain lock with a rubber band in the video above. In short, it's a matter of attaching the rubber band to the lock and the door handle (it looks like a handle rather than a knob is important). Before you go asking why he doesn't just slide the lock open with his hand (which I wondered briefly myself), remember: Chain locks work because you can't slide it open with your hand. As you start sliding the lock toward open, the tension between the wall and the door will pull the door closed before you can slide it all the way open.

Whether you're picking a lock, cracking a padlock, or hacking a Wi-Fi password, the goal is often less about knowing how to "break in" to something and more about understanding the security limitations a tool provides. The same holds true here. Also, who knows? It could come in handy next time little Timmy locks himself in the hotel room and won't come out.